1. Field of the Invention
This invention relates generally to an apparatus and method for installing a liner within a pipeline, and more particularly, to an apparatus and method for installing a liner in man-entry sized pipes such as underground sewer pipes and the like.
2. Description of the Related Art
Sewer pipes are typically constructed of concrete and configured to transport massive volumes of sewage on a daily basis. Most concrete sewer pipes deteriorate over time due to repeated exposures to corrosive sewer gases such as hydrogen sulfide. Corrosive sewer gas can erode the inner walls of the sewer pipes and form cracks that would allow sewer gas to escape and ground water to seep through. To address this problem, systems and methods have been developed to rehabilitate the older sewer pipes. One such method involves retrofitting the pipe with a liner on its inner surface. The liner is typically made of corrosion resistant material such as polyethylene or polyvinylchloride (PVC). A commonly used method involves applying an annular slipliner to the conduit by inserting a rigid PVC pipe into the bore of the conduit so as to provide a corrosion resistant passageway. A cement grout is usually injected into the cavity between the pipe and the conduit to affix the pipe to the conduit. However, the thickness of the pipe in conjunction with the annular gap created between the conduit and the pipe can reduce the effective diameter of the sewer passageway, which in turns reduces the amount of sewage that can be transported.
An alternative pipe liner has been recently developed to address the shortcomings associated with the above-described annular slipliners. The new pipe liner is generally comprised of a flexible sheet of material such as PVC that conforms to the contours of the inner surface of the conduit. The flexible sheet liner is typically much thinner than the annular slipliners and thus does not noticeably reduce the diameter of the sewer passageway. However, the process of applying the sheet liner to the conduit can be labor intensive as it involves positioning a relatively large sheet of liner such as PVC adjacent the inside surface of the sewer pipe and then injecting grout between the liner and the sewer wall to secure the liner to the wall. It can be appreciated that the PVC sheet is typically very heavy and therefore difficult to place and hold in position before grout is applied to bond the sheet to the pipe wall. Moreover, significant time and labor are often required to carry the heavy roll of PVC material into a man-entry sized conduit, unroll the material, and then lift the material so that it is positioned adjacent the inside surface of the conduit before grout is applied. Presently, almost the entire sheet lining process is performed manually and the inventor is not aware of any equipment that has been developed to facilitate the placement of sheet liners inside sewer pipes because the process of retrofitting sewer pipes with liner sheets is relatively new in itself.
Hence from the foregoing, it will be appreciated that there is a need for an apparatus and method that will facilitate application of a sheet liner inside a man-entry sized pipe line. To this end, this is a particular need for an apparatus or process that reduces the amount of time and labor required to apply a sheet liner to the inner walls of sewer pipes.